From Rivers to the Ocean: The Dynamics of Freshwater Export from Hudson Strait

学术价值：从极地到亚极区沿地形边缘流动的新鲜、上浮的洋流对地区和全球气候都有深远的影响。它们还通过影响表层的养分供应，对下游的生态系统和渔业产生重大影响。然而，我们对极地盆地和沿海地区不同的淡水输入如何转化为下游观测到的可变新鲜水流的了解有限。在北极淡水出口增加，模型预测未来会有更大的出口之际，识别和理解支配这种转变的过程变得更加紧迫。哈德逊海峡的新系泊数据提供了在通过海峡与大范围海洋相连的半封闭盆地中研究来自多条河流的大河流输入与北极淡水流入的转化的机会。哈德逊海峡是北大西洋淡水的第三大贡献者，也是拉布拉多海流的主要淡水贡献者，拉布拉多海流的水域影响着整个北美东北部海岸的陆架斜坡水域。它的流出在每天到年际的时间尺度上变化很大。这种变化的潜在来源包括时空分布的径流来源、本地强迫和远程大气强迫以及来自Davis海峡的入流变化。拟议工作的目标是：(1)确定在每日至年际时间尺度上影响淡水输送的过程，以及(2)确定淡水输送与河流径流、戴维斯海峡输送和拉布拉多洋流输送之间的关系。这些目标将通过分析哈德逊海峡新的和历史的系泊和水文数据，辅之以气象数据、河流数据和我们的一位加拿大同事运行的区域数值模式来实现。这项研究的结果不仅将提高我们对格陵兰岛以西淡水路径的了解，还将增强我们对淡水在流向亚极地地区的过程中的总体理解。广泛影响：这项工作不仅与全球气候和北美东北部海岸相关，而且对海峡上游地区同样重要，该地区支持着大量的本地人口和多样化的生态系统，已被确定为特别容易受到气候变化影响的地区。拟议的工作将促进国际合作和跨学科合作，并弥合极地和亚极地区之间的差距。该项目将涉及一名博士后、一名美国和一名加拿大研究生，他们将从接触到多元化的国际科学家群体中受益。作为拟议工作的一部分，我们开始与一位具有北极探险和因纽特文化背景的有成就的作家合作。这种合作的直接结果是将在美国各地的博物馆举办一系列讲座，通过利用亨利·哈德森航行哈德逊海峡和海湾400周年来比较和对比科学和地理探索。未来的计划包括在自然历史/科普杂志上发表文章，以及在哈德逊湾和海峡沿岸的因纽特社区举办一系列讲座。

Intellectual Merit: The fresh, buoyant currents which travel along the topographic margins from the polar to the subpolar regions have a profound influence on both the regional and global climate. They also have a strong impact on the ecosystems and fisheries downstream by affecting nutrient supply to the surface layer. Yet our knowledge of how distinct freshwater inputs in the polar basins and coastal regions are transformed into the variable, fresh flow observed downstream is limited. Identifying and understanding the processes that govern this transformation is even more pressing at a time when there is increased freshwater export from the Arctic and models predict an even greater export in the future. The opportunity to study the transformation of a large riverine input, from multiple rivers, combined with the inflow of Arctic freshwater, in a semi-enclosed basin connected to the large scale ocean through a strait is provided by new moored data from Hudson Strait. Hudson Strait is the third largest contributor of freshwater to the North Atlantic and a major contributor of fresh water to the Labrador Current, whose waters influence the shelf-slope waters of the entire northeastern North American coast. Its outflow is strongly varying on daily to interannual timescales. Amongst the potential sources of this variability are the spatially and temporally distributed runoff sources, local forcing and remote atmospheric forcing and variations in the inflow from Davis Strait. The goal of the work proposed is to: (1) identify the processes influencing the freshwater transport on daily to interannual timescales, and (2) determine the relationship between the transport and river run-off, the Davis Strait transport and the Labrador Current transport. These goals will be achieved through the analysis of new and historical moored and hydrographic data from Hudson Strait, complemented by meteorological data, river data and a regional numerical model run by one of our Canadian colleagues. The results from this study will not only improve our knowledge of the freshwater pathways west of Greenland but, also, augment our general understanding of the processes that transform freshwater on its route to the subpolar regions.Broader Impacts: This work is not only of relevance to global climate and to the northeastern North American coast, but it is equally important for the region upstream of the strait which supports a large native population and diverse ecosystem and that has been identified as one particularly susceptible to climate change. The proposed work will foster international collaborations and those across disciplines and bridge the gap between the polar and subpolar regions. The project will involve a post-doc, a U.S. and a Canadian graduate student who will benefit from the exposure to a diverse, international group of scientists. As part of the proposed work we have initiated a collaboration with an accomplished writer with a background in Arctic exploration and Inuit culture. An immediate result of this collaboration is a series of lectures to be conducted in museums around the U.S. that will compare and contrast scientific and geographic exploration by exploiting the 400 year anniversary of Henry Hudson's voyage into Hudson Strait and Bay. Future plans include articles in natural history/popular science magazines and a series of lectures in the Inuit communities along the shores of Hudson Bay and Strait.